*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19781
19790
19800
19810
19820
19830
19840
19850
19860
19873
198814
19891
19903
19917
19926
19936
19941
19959
199615
199711
19981
19991
20000
20011
20024
20032
20041
20052
20061
20070
20081
20093
20101
20113
20122
20132
20141
20154
20164
20173
20180
Total114